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1 Maxim > Design Support > Technical Documents > Application Notes > Microcontrollers > APP 4199 Keywords: 8051,single-cycle,upgrade,flash,high speed,performance APPLICATION NOTE 4199 Porting Applications from the High-Speed Micro Family to Ultra-High-Speed Flash Microcontrollers Mar 28, 2008 Abstract: There are many reasons to upgrade older 8051 designs that use high-speed microcontrollers (DS80C310/DS80C320/DS80C323/DS8xC520) to the newer ultra-high-speed flash microcontrollers (DS89C430/DS89C450). Incentives to upgrade include higher performance, additional features and peripherals, and the flexibility of internal flash memory. This application note discusses some important differences between the two microcontroller families and explains how to upgrade from the high-speed to the ultra-high-speed devices. Overview Maxim's high-speed microcontroller family includes a wide variety of 8051 microcontrollers which execute instructions at a faster 4 clocks-per-machine-cycle rate compared to the 8051's original 12 clocks-permachine cycle speed. Some of the high-speed microcontrollers operate entirely from external program memory, such as the DS80C310, while others contain internal EPROM or ROM program memory, such as the DS87C520/DS83C520. All of these high-speed devices are pin-compatible with existing 8051 microcontrollers, so designs can be upgraded in most cases simply by dropping in a faster device and making minor software adjustments. In a similar manner, the ultra-high-speed flash microcontrollers can be used as drop-in upgrades for high-speed microcontroller designs. These newer, more powerful microcontrollers, which include the DS89C430/DS89C450, offer important improvements: expanded internal program flash memory (up to 64kB); and a redesigned, ultra-high-speed microcontroller core capable of executing instructions in a single clock cycle for up to a 12x speed improvement over the original 8051 design. This application note discusses how to upgrade from the high-speed microcontrollers to ultra-high-speed flash devices. The article also outlines differences in feature sets, pinout details, and SFR changes that must be considered when upgrading a design. General References For general programming guidelines for the following devices, consult the High-Speed Microcontroller User's Guide (PDF). DS80C310 High-Speed Microcontroller DS80C320 High-Speed Low-Power Microcontroller DS80C323 High-Speed Low-Power Microcontroller Page 1 of 10

2 DS83C520 High-Speed ROM Microcontroller DS87C520 High-Speed EPROM Microcontroller For general programming guidelines for the following devices, consult the Ultra-High-Speed Flash Microcontroller User's Guide (PDF). DS89C430 Ultra-High-Speed Flash Microcontroller DS89C450 Ultra-High-Speed Flash Microcontroller Basic Device Features Table 1. Comparison of Device Features Feature DS80C310 DS80C320 DS87C520 DS89C430 DS80C323 DS83C520 DS89C450 Clocks per Machine Cycle Operating Voltage Range (V) 4.5 to to 5.5 (DS80C320) 4.5 to to to 5.5 (DS80C323) Clock Rate (MHz, max) (DS80C320) 18 (DS80C323) Instruction Execution Time (ns, min) (DS80C320) 222 (DS80C323) Crystal Multiplier (x2 or x4) Ring Oscillator Internal Program Memory None None 16kB 16kB (DS89C430) 64kB (DS89C450) Internal Register Memory (Bytes) Internal MOVX Memory None None 1kB 1kB Serial Ports (UARTs) External Interrupts Port Pins (with Bus Active) Port Pins (max) Timer/Counters Three/16- bit Three/16-bit Three/16- bit Watchdog Dual Data Pointers Autoincrement/Decrement Stop Mode Power-On Reset Power-Fail Interrupt Three/16-bit Page 2 of 10

3 Device Pinout Scheme Table 2. Device Pinout Differences DIP PLCC TQFP DS80C310 DS80C320 DS80C323 DS87C520 DS83C520 DS89C430 DS89C P1.0 (T2) P1.0 (T2) P1.0 (T2) P1.0 (T2) P1.1 (T2EX) P1.1 (T2EX) P1.1 (T2EX) P1.1 (T2EX) P1.2 P1.2 (RXD1) P1.2 (RXD1) P1.2 (RXD1) P1.3 P1.3 (TXD1) P1.3 (TXD1) P1.3 (TXD1) P1.4 (INT2) P1.4 (INT2) P1.4 (INT2) P1.4 (INT2) P1.5 (nint3) P1.5 (nint3) P1.5 (nint3) P1.5 (nint3) P1.6 (INT4) P1.6 (INT4) P1.6 (INT4) P1.6 (INT4) P1.7 (nint5) P1.7 (nint5) P1.7 (nint5) P1.7 (nint5) RST RST RST RST P3.0 (RXD0) P3.0 (RXD0) P3.0 (RXD0) P3.0 (RXD0) P3.1 (TXD0) P3.1 (TXD0) P3.1 (TXD0) P3.1 (TXD0) P3.2 (nint0) P3.2 (nint0) P3.2 (nint0) P3.2 (nint0) P3.3 (nint1) P3.3 (nint1) P3.3 (nint1) P3.3 (nint1) P3.4 (T0) P3.4 (T0) P3.4 (T0) P3.4 (T0) P3.5 (T1) P3.5 (T1) P3.5 (T1) P3.5 (T1) P3.6 (nwr) P3.6 (nwr) P3.6 (nwr) P3.6 (nwr) P3.7 (nrd) P3.7 (nrd) P3.7 (nrd) P3.7 (nrd) XTAL2 XTAL2 XTAL2 XTAL XTAL1 XTAL1 XTAL1 XTAL , 23 16, 17 GND GND GND GND 1 39 GND N/C (can be connected to GND if desired) GND GND A8 (P2.0) A8 (P2.0) A8 (P2.0) A8 (P2.0) A9 (P2.1) A9 (P2.1) A9 (P2.1) A9 (P2.1) A10 (P2.2) A10 (P2.2) A10 (P2.2) A10 (P2.2) A11 (P2.3) A11 (P2.3) A11 (P2.3) A11 (P2.3) A12 (P2.4) A12 (P2.4) A12 (P2.4) A12 (P2.4) A13 (P2.5) A13 (P2.5) A13 (P2.5) A13 (P2.5) A14 (P2.6) A14 (P2.6) A14 (P2.6) A14 (P2.6) A15 (P2.7) A15 (P2.7) A15 (P2.7) A15 (P2.7) npsen npsen npsen npsen ALE ALE ALE ALE/nPROG nea nea nea nea AD7 AD7 AD7 (P0.7) AD7 (P0.7) AD6 AD6 AD6 (P0.6) AD6 (P0.6) AD5 AD5 AD5 (P0.5) AD5 (P0.5) Page 3 of 10

4 AD4 AD4 AD4 (P0.4) AD4 (P0.4) AD3 AD3 AD3 (P0.3) AD3 (P0.3) AD2 AD2 AD2 (P0.2) AD2 (P0.2) AD1 AD1 AD1 (P0.1) AD1 (P0.1) AD0 AD0 AD0 (P0.0) AD0 (P0.0) V CC (+5V) V CC +5V (DS80C320) V CC +3V (DS80C323) V CC (+5V) V CC (+5V) 12 6 N/C N/C N/C V CC (+5V) N/C N/C N/C GND Device Registers Table 3. SFR Map Comparisons Address DS80C310 DS80C320 DS87C520 DS89C430 DS80C323 DS83C520 DS89C450 80h P0 P0 81h SP SP SP SP 82h DPL DPL DPL DPL 83h DPH DPH DPH DPH 84h DPL1 DPL1 DPL1 DPL1 85h DPH1 DPH1 DPH1 DPH1 86h DPS DPS DPS DPS 87h PCON PCON PCON PCON 88h TCON TCON TCON TCON 89h TMOD TMOD TMOD TMOD 8Ah TL0 TL0 TL0 TL0 8Bh TL1 TL1 TL1 TL1 8Ch TH0 TH0 TH0 TH0 8Dh TH1 TH1 TH1 TH1 8Eh CKCON CKCON CKCON CKCON 90h P1 P1 P1 P1 91h EXIF EXIF EXIF EXIF 96h CKMOD 98h SCON SCON0 SCON0 SCON0 99h SBUF SBUF0 SBUF0 SBUF0 9Dh ACON A0h P2 P2 P2 P2 A8h IE IE IE IE A9h SADDR0 SADDR0 SADDR0 SADDR0 AAh SADDR1 SADDR1 SADDR1 B0h P3 P3 P3 P3 Page 4 of 10

5 B1h IP1 B8h IP IP IP IP0 B9h SADEN0 SADEN0 SADEN0 SADEN0 BAh SADEN1 SADEN1 SADEN1 C0h SCON1 SCON1 SCON1 C1h SBUF1 SBUF1 SBUF1 C2h ROMSIZE ROMSIZE C4h PMR PMR C5h STATUS STATUS STATUS STATUS C7h TA TA TA C8h T2CON T2CON T2CON T2CON C9h T2MOD T2MOD T2MOD T2MOD CAh RCAP2L RCAP2L RCAP2L RCAP2L CBh RCAP2H RCAP2H RCAP2H RCAP2H CCh TL2 TL2 TL2 TL2 CDh TH2 TH2 TH2 TH2 D0h PSW PSW PSW PSW D5h FCNTL D6h FDATA D8h WDCON WDCON WDCON WDCON E0h ACC ACC ACC ACC E8h EIE EIE EIE EIE F0h B B B B F1h EIP1 F8h EIP EIP EIP EIP0 Table 4. SFR Function Differences SFR Bit(s) Differences P0 DS8xC520/DS89C430/DS89C450 only; controls Port 0 pins. 4 (AID) DS89C430/DS89C450 only; controls the autoincrement/decrement function for the active data pointer. DPS 5 (TSL) DS89C430/DS89C450 only; enables automatic toggling between data pointers after certain opcodes. 6 (ID0) DS89C430/DS89C450 only; controls the effect of INC DPTR (increment or decrement) on DPTR. 7 (ID1) DS89C430/DS89C450 only; controls the effect of INC DPTR (increment or decrement) on DPTR1. PCON 4 (OFDE) DS89C430/DS89C450 only; crystal oscillator fail detection enable. 5 (OFDF) DS89C430/DS89C450 only; crystal oscillator fail detection flag. CKCON 7 (WD1) 6 (WD0) On all devices except the DS80C310; these bits control the watchdog timer period. Page 5 of 10

6 EXIF CKMOD ACON IE 0 (BGS) 1 (RGSL) 2 (RGMD) 3 SADDR1 IP1 SADEN1 SCON1 SBUF1 ROMSIZE 3 (T0MH) 4 (T1MH) 5 (T2MH) 5 (PAGES0) 6 (PAGES1) 7 (PAGEE) 6 (ES1) 2:0 (RMS2:0) 3 (PRAME) 1:0 (DME1:0) 2 On all devices except the DS80C310; this bit enables/disables the bandgap reference during stop mode. On all devices except the DS80C310; this bit controls execution from the ring oscillator during the crystal warmup period. On all devices except the DS80C310; this flag indicates the current clock source (ring or crystal). DS8xC520 (XT/nRG); selects the ring oscillator or crystal as the desired clock source. DS89C430/DS89C450 (CKRY); indicates that the crystal oscillator or crystal multiplier has completed its warmup period. DS89C430/DS89C450 only; allows Timer 0 to run directly from the system clock (clock/1). DS89C430/DS89C450 only; allows Timer 1 to run directly from the system clock (clock/1). DS89C430/DS89C450 only; allows Timer 2 to run directly from the system clock (clock/1). DS89C430/DS89C450 only; selects the page-mode configuration for external bus operations. DS89C430/DS89C450 only; enables page mode (as opposed to the standard 8051 expanded bus mode) for external bus operations. On all devices except the DS80C310; this bit enables/disables the serial port 1 interrupt. On all devices except the DS80C310; this register controls the slave address for serial port 1. DS89C430/DS89C450 only; this register combines with the settings in IP0/IP to provide four priority-level settings for each interrupt (as opposed to two settings with IP only). On all devices except the DS80C310; this register sets the slave address mask for serial port 1. On all devices except the DS80C310; this register controls mode settings for serial port 1. On all devices except the DS80C310; this register provides the input/output buffer for serial port 1. DS8xC520/DS89C430/DS89C450 only; selects the range of on-chip EPROM/flash that maps into program space. DS89C430/DS89C450 only; enables/disables mapping of the 1kB internal RAM into program space. DS8xC520/DS89C430/DS89C450 only; controls mapping of internal data memory into data space. DS8xC520 (ALEOFF); when set to 1, disables ALE during on-board memory access. DS89C430/DS89C450 (ALEON); when set to 0, disables ALE during on-board memory access. DS8xC520 (XTOFF); when set to 1, disables the crystal oscillator (must run from Page 6 of 10

7 PMR 3 ring). DS89C430/DS89C450 (4X/n2X); sets the mode for the crystal multiplier. STATUS TA WDCON EIE EIP 4 (CTM) DS89C430/DS89C450 only; when set to 1, enables the crystal multiplier. 5 (SWB) DS8xC520/DS89C430/DS89C450 only; when set to 1, enables automatic switchback mode. 7:6 (CD1:0) 0 (SPRA0) 1 (SPTA0) 2 (SPRA1) 3 (SPTA0) 4 (XTUP) 5 (LIP) 6 (HIP) 7 (PIP) 7:5 (PIS2:0) DS8xC520/DS89C430/DS89C450 only; controls the clock division or multiplier mode. Note that the available settings are different on the DS8xC520/DS89C430/DS89C450. DS8xC520/DS89C430/DS89C450 only; indicates that a character is currently being received on serial port 0. DS8xC520/DS9C430/DS89C450 only; indicates that a character is currently being transmitted on serial port 0. DS8xC520/DS89C430/DS89C450 only; indicates that a character is currently being received on serial port 1. DS8xC520/DS89C430/DS89C450 only; indicates that a character is currently being transmitted on serial port 1. DS8xC520 only; indicates whether the crystal oscillator has completed its warmup cycle. DS80C320/DS80C323/DS8xC520 only; indicates that a low-priority interrupt is currently being serviced. DS80C320/DS80C323/DS8xC520 only; indicates that a high-priority interrupt is currently being serviced. DS80C320/DS80C323/DS8xC520 only; indicates that a power-fail priority interrupt is currently being serviced. DS89C430/DS89C450 only; indicates that the priority level of the interrupt is being serviced. On all except the DS80C310; controls the Timed Access register protection mechanism. 0 (RWT) On all devices except the DS80C310; resets the watchdog timer. 1 (EWT) On all devices except the DS80C310; enables/disables the watchdog timer. 2 (WTRF) On all devices except the DS80C310; indicates that a watchdog timer reset has occurred. 3 (WDIF) On all devices except the DS80C310; indicates that a watchdog timer interrupt has occurred. 4 (PFI) On all devices except the DS80C310; indicates that a power-fail interrupt has occurred. 5 (EPFI) On all devices except the DS80C310; enables/disables the power-fail interrupt. 6 (POR) On all devices; indicates that a power-on reset has occurred. 7 On all devices except the DS80C310; enables/disables baud-rate doubling mode (SMOD_1) for serial port 1. 4 (EWDI) On all devices except the DS80C310; enables/disables interrupts from the watchdog timer. 3:0 (PX5:2) On all devices except the DS89C430/DS89C450; sets high/low priority for external interrupts 2, 3, 4, and 5. DS80C320/DS80C323/DS8xC520 only; sets high/low priority for the watchdog Page 7 of 10

8 EIP1, EIP0 4 (PWDI) timer interrupt. DS89C430/DS89C450 only; these registers set priority levels 0 3 for the watchdog timer interrupt and external interrupts 2, 3, 4, and 5. Single-Cycle Execution The ultra-high-speed DS89C430/DS89C450 processors require only a single clock to execute a singlecycle instruction, which is a 4x speed improvement over the DS80C310/DS80C320/DS80C323/DS8xC520. These latter high-speed microcontrollers require 4 clocks to complete a machine cycle. This difference in clock speed means that simply replacing one of the highspeed devices with the DS89C430/DS89C450 will result in up to a 4x increase in execution speed at the same crystal frequency. Nonvolatile Memory The DS80C310/DS80C320/DS80C323 have no programmable internal code memory and require external memory for code storage. The DS8xC520 improves on this memory scheme by including 16kB of program EPROM. When porting from the DS80C310/DS80C320/DS80C323 to the DS89C430/DS89C450, application code that was stored in external ROM, flash, or EPROM memory can be relocated to the internal flash memory of the ultra-high-speed processors. The DS89C430 provides the same amount of internal program memory (16kB) as the DS8xC520, so any applications stored in the DS8xC520 should fit into the DS89C430 without modification. Applications stored in external program memory will fit in the 64kB internal flash memory of the DS89C450, as long as port-pin banking was not used to expand program memory beyond 64kB. Finally, since the DS89C430/DS89C450 still support the standard 8051 multiplexed address bus scheme, external code and program memory can still be used in the application, if desired. Serial Bootloader While the DS8xC520 includes internal EPROM program memory, there is no provision for in-system or in-application programming (IAP) of the internal EPROM. A stand-alone programmer must be used to load the EPROM, and the DS8xC520 must be removed from (or electrically isolated from) the rest of the system for reprogramming to occur. (It is possible, however, to implement a user loader on the DS8xC520 which allows an external program or data EPROM or nonvolatile RAM to be reloaded under application control. See application note 102, "Using the High-Speed Microcontroller as a Bootstrap Loader," for more details.) The DS89C430/DS89C450 improve on this programming process by including a serial bootloader function. This function allows program memory to be reloaded by using a simple ASCII-based protocol. The serial bootloader is implemented in the microcontroller's on-board ROM, so no code space is consumed by this feature. In addition, the FCNTL and FDATA registers can be used for IAP, so parts of the flash can be erased and rewritten under user control. GPIO Port 0 Since the DS89C430/DS89C450 (like the DS8xC520) can operate without external code or data memory if desired, their eight Port 0 pins (which act as AD[7:0] when the multiplexed bus is active) can be used Page 8 of 10

9 as general-purpose I/O (GPIOs). There are other I/O pins that can be reclaimed for general-purpose use when the external bus is not used: the eight Port 2 pins (P2[7:0]); the P3.6 (nwr) pins; and P3.7 (nrd) pins. Unlike the Port 2 and Port 3 pins, however, the Port 0 pins use open-drain output drivers. This means that pullup resistors must be used, if these pins are to act as outputs. If the Port 0 pins will be used as inputs (driven externally), no pullup resistors are required. Divide-by-1 Timer Clocks The CKMOD register on the DS89C430/DS89C450 adds the ability to drive the three timers (Timer 0, Timer 1, and Timer 2) directly from the system clock (as opposed to the standard divide-by-4 and divideby-12 options). This high-speed select mode (controlled by the bits T0MH, T1MH, and T2MH) defaults to disable following reset to make the timers compatible with code written for the DS80C310/DS80C320/DS80C323/DS8xC520. Crystal Multiplier The DS89C430/SD89C450 include an on-board crystal multiplier which allows the crystal frequency to be boosted by 2x or 4x. This means that a 5MHz crystal can be used to generate a 5MHz, 10MHz, or 20MHz clock as needed. Five-Level Interrupt Priority The DS89C430/DS89C450 expand the programmable interrupt priority scheme to allow any of the external interrupts, timer interrupts, serial port interrupts, or the watchdog interrupt to be assigned a userdefined priority level from 0 (lowest) to 3 (highest nonpower-fail priority). The highest priority level, level 4, is reserved for the power-fail interrupt. This system is backwards compatible with the low-/highprogrammable priority scheme used by the DS80C310/DS80C320/DS80C323/DS8xC520. Power-Supply Considerations With their increased processing power, the DS89C430/DS89C450 have higher power-supply requirements than the microcontrollers in the high-speed family. At the maximum crystal frequency in active mode, the DS89C430/DS89C450 can draw up to 110mA (75mA, typ) in supply current. Consequently, when upgrading to the DS89C430/DS89C450, their power consumption may require changes to the power-supply circuit of a high-speed design. Refer to the device's data sheet for more details. Digital Noise Considerations The improved performance of the ultra-high-speed flash microcontrollers is the result of a core redesign that reduces machine cycle time and significantly increases internal switching speeds. Because of this, system designers can see a slight increase in digital noise when an ultra-high-speed flash microcontroller directly replaces a high-speed microcontroller. System designers should investigate what, if any, effect the increase in performance will have on their design. In some cases, it may be necessary to add additional bypass capacitors at the microcontroller or apply some other filtering method to reduce digital noise. Page 9 of 10

10 Software Timing Loops Application code that generates precise timing using software loops may need to be adjusted when moving from the high-speed microcontrollers to the ultra-high-speed devices. Timing loops of this type must be examined on a case-by-case basis, however, since not all instructions show the maximum 4x speed improvement when moving to the DS89C430/DS89C450. For example, while "ADD A, R0" executes in 4 clock cycles on any of the high-speed microcontrollers and in 1 clock cycle on the DS89C430/DS89C450 (a 4x speed increase), the instruction "ADD goes from 4 cycles on the high-speed devices to 2 cycles on the DS89C430/DS89C450 (a 2x speed increase). Refer to the "Instruction Timing" sections in both the High-Speed Microcontroller User's Guide and the Ultra-High- Speed Flash Microcontroller User's Guide for more details. Related Parts DS80C310 High-Speed Microcontroller Free Samples DS80C320 High-Speed/Low-Power Microcontrollers Free Samples DS80C323 High-Speed/Low-Power Microcontrollers Free Samples DS83C520 EPROM/ROM High-Speed Microcontrollers DS87C520 EPROM/ROM High-Speed Microcontrollers Free Samples DS89C430 Ultra-High-Speed Flash Microcontrollers Free Samples DS89C450 Ultra-High-Speed Flash Microcontrollers Free Samples More Information For Technical Support: For Samples: Other Questions and Comments: Application Note 4199: APPLICATION NOTE 4199, AN4199, AN 4199, APP4199, Appnote4199, Appnote 4199 Copyright by Maxim Integrated Products Additional Legal Notices: Page 10 of 10

High-Speed Microcontroller User s Guide

Rev: 338 High-Speed Microcontroller User s Guide Maxim Integrated Products 1 TABLE OF CONTENTS High-Speed Microcontroller User s Guide 1. INTRODUCTION...9 2. ORDERING INFORMATION...1 3. ARCHITECTURE...11